The heart includes valves which are present at the outlet of the right ventricle (pulmonary or tricuspid valve) and of the left ventricle (aortic or mitral valve).
These valves ensure one way circulation of blood flow, avoiding blood backflow at the end of the ventricle contraction.
However, diseases or deformities affect proper operation of the valves.
In particular, the latter may suffer from calcification thus allowing backflow or regurgitation towards the ventricle at the auricle having expelled the blood flow. The regurgitation problem leads to abnormal expansion of the ventricle which finally produces heart failure.
In order to treat this type of disease in a surgical way the implantation of an endovalve between the leaflets of the affected native valve is known. This endovalve comprises a tubular endoprosthesis formed by a self-expandable trellis and a flexible obturator or valve most often made in a tissue of animal origin. The flexible obturator is permanently fixed in the endoprosthesis.
Such endovalves are implantable via an endoluminal route, which considerably limits the risks associated with implantation of the valve, notably in terms of mortality.
In certain cases, the endovalves do not give entire satisfaction after their implantation. Indeed, although the outer surface of the endoprosthesis is spontaneously applied against the seat of the native valve, by flattening the leaflets between the seat and the outer surface of the endoprosthesis, leaks may subsist around the outer surface of the endoprosthesis, notably at the joints defined between the leaflets of the native valve. These leaks occur in more than 50% of the patients having been subject to such an operation.
In order to overcome this problem, US 2005/0283231 describes an implant comprising an endoprosthesis and a prosthetic valve fixed in the endoprosthesis. The leaflets of the prosthetic valve are extended with foldable segments around the endoprosthesis so as to be interposed between the wall of the conduit and the outer surface of the endoprosthesis. These folded segments around the endoprosthesis are able to fill at least partly the leaks which may occur around the implant.
However, each folded segment is bound to the valve. It is therefore difficult to position it with accuracy, in particular with respect to the endoprosthesis and/or to the blood flow conduit in which the implant is positioned. In particular, the position at which the folded segment has to be positioned in the native valve is difficult to determine for ensuring a good seal around the endoprosthesis.